Abstract

Many of the theoretical concepts in photogrammetry are difficult to understand
by means of equations and figures. Furthermore, commercial software is
not usually adapted to the requirements of teaching and learning. However,
photogrammetric simulation software based on virtual worlds can be used to
improve both learning and understanding of complex geometrical issues such as
the generation of true ortho-images in urban areas, and assists in training and
skills development. This paper tackles image orthorectification by means of a
photogrammetric simulation and its generation based on digital elevation/
building/surface models, and the interior and exterior orientation parameters of
the image sensor, namely, a digital camera. Internal processes such as masking
and visibility analysis which are necessary to yield successful true ortho-images
are reported, with examples from both simple and complex urban environments.